Research Study And Fractal Study On Rocklike Materials Specimen With Multicracks Under Biaxial Compression

Instability failure process of rock substance in the project is the rock of crack initiation in engineering perturbations, expansion, and through the process; a lot of rock engineering practice shows that its instability and failure of rock in fractured rock mass distribution and form in which the surrounding environment and other factors related to stress, the study deformation and failure regularity and pattern through fractured rock mass is of great significance. Taking pre-Multi category Cracked rock specimens under biaxial compression crack propagation and damage characteristic specimen for analysis,, Main achievements are concluded as follows:(1)Preparation of a group of 120 crack inclination of 30°,45°,60° and a crack in the number of 10,15,20,25 and 30 multi-class rock Cracked rock specimens by double shear rheometer axle load, to achieve different load test specimen under lateral stress(0.5Mpa, 1.0Mpa, 1.5Mpa and 2.0Mpa) conditions; record and describe crack propagation experiment specimen.(2)Obtain specimens axial stress- strain relation curve, the curve showing S-type, specimen crack after the closing stage, the stage of elastic deformation,crack initiation and propagation(or local deformation of the specimen), strain softening stage;In a different number of lateral pressure and crack its peak intensity on the specimen axial obviously, increase the number of cracks, and its peak intensity significantly reduced; lateral pressure increases, the peak intensity increases; crack angle is 30°~ 45°than the inclination angle of 60°to the peak intensity lower performance.(3)Further analysis of the specimen at increasing the number of cracks, damage in the form of specimens from wing to wing to pull the progressive development of cracks and pull crack secondary composite shear cracks damage; the effects of different patterns of lateral pressure through its main It showed that with the increase of lateral stress, through the crack pattern presented by the extended wing and wing axial secondary shear crack + crack + crack evolved wing axial and lateral secondary shear crack; when lateral pressure of 0.5 Mpa, the specimen in the specimen generally occur through local, to wing cracks+axially oriented secondary shear crack; when the lateral pressure is increased to 2.0Mpa, different crack angle,multi-Cracked the failure mode was diagonally through the destruction of native crack along the inclination direction of wing cracks.(4)Crack through different multi-body specimens biaxial loading test at different lateral pressure, the degree of crack specimen damage process using measured specimen box fractal dimension damage during different stress points specimens crack analysis test member fractal dimension trends in the destruction process, Analyzing the results, the higher the degree of destruction of specimens,their relevance as possible, the fractal dimension of the specimen showed a tendency to increase; high specimen crack distribution level, the more intensive, the higher its fractal dimension measurement.